What follows is a fairly lengthy letter submitted today by a lister on the mbz.org diesel list. Since the weather's warming up, and there's been some discussion of the refrigerant in question, I'm submitting this as a word to the wise. While the refrigerant in question is Duracool, the same potential exists with other hydrocarbon refrigerants.
Hopefully this gentleman's engine isn't damaged, but his follow up emails weren't promising. Just so I'm clear what follows IS NOT FROM ME, so there's no need to respond to his questions. This is for your information only.
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OK Guys, this one is weird.
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As most of you probably know, I use Duracool 12a as my refridgerant in my car, and I really like the cooling properties. However, I had been having a slight leak on my low-pressure switch that attaches to the condenser-side of the accumulator. Well, today I hooked up my gauges and wanted to add some to it. The recommended low-side pressure is 40 PSI at 1500 RPM. Well, by gauges were leaking pretty badly (actually the hoses, but you know what I mean), so I scraped them, and put in a can directly. It still needed the amount anyway. Well, upon doing so, the seal were the low-pressure switch is blew, creating a huge misting cloud of Duracool 12a. This is where it gets interesting. I immediatly disconnected the can from the manifold, and suddenly the engine's RPM went through the roof! Soot was blowing everywhere out of my exhaust, and the governor was the only thing holding it down, I think... and hope. I ran to the ignition and pulled the key out, but it continued to run, so I hit the manual kill, and it still ran. Finally, after an eternal 5 seconds or so, it died. I was completely confused as to what might have caused it, and then I realized what happened. Duracool 12a is a mix of two hydrocarbons: isobutane and isopropane. Well, seeing as the accumulator is right by the air intake, those fumes got sucked right in, sending the engine speed sky-high. I cut off the supply of diesel, and it continued to run on the Duracool!!!! Scared the crap out of me!!!! So, after a while, I went out and tried to start it again (all of the Duracool was long gone by this time), and it took a few tries.
Once it finally started (crappy firing, took a lot of persistence) the idle was INCREDIBLY rough and down to about 600 RPM from 750 RPM. I reved it some, thinking that maybe when it took off it had dislodged a lot of soot. Well, a lot of soot came out, but smoke too... and quite a bit.
So what have I done? It still idles just as rough. Have I blown an internal seal or something? Please, tell me anything. I am worried to death here and really need some guidance. Thanks in advance, and be careful of those low-pressure switches.